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robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to Jack_in_VA

Re: Generator doesn't work with Power Vent Hot Water Heater

said by Jack_in_VA:

I don't recall specifying that I was talking about a gas fired water heater.

That's what the thread is about. I responded to gary2k and then you responded to what I said.

Gas water heater / generator / extension cord / neutral ground bond. It connects to the electric system of the house. It is not isolated.

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus

said by robbin:

said by Jack_in_VA:

I don't recall specifying that I was talking about a gas fired water heater.

That's what the thread is about. I responded to gary2k and then you responded to what I said.

Gas water heater / generator / extension cord / neutral ground bond. It connects to the electric system of the house. It is not isolated.

How's that? If the water heater is disconnected from the breaker, then connected to the generator via an extension cord, the generator's ground and neutral are bonded and then the generator's frame is connected (bonded, ideally) to the house ground, HOW are they "not isolated?"

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
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reply to sk1939

Re: Generator doesn't work with Direct Vent Hot Water Heater

said by sk1939:

said by garys_2k:

No, it would trip the generator's breaker.

Yes and no, it can take quite a bit of current for a breaker to trip depending on the type of short. If there is an arc (which typically is the cause of fires next to overloads) then it won't trip at all.

You did say "dead short." If you want to now talk about an overload, that's fine, but I can't see how any fault current would be available elsewhere on the system. The fault current would run back to the source, the generator.
said by sk1939:

said by garys_2k:


Generators are rated to work with extension cords, that's why there are outlets on them. Using them is perfectly safe (as long as you don't cut them or trip over them) and consistent with their directions and the NEC.

Again yes, but you can't really (even if you could it would be wrong because it's against code) power a water heater off of an extension cord (other than a tankless single sink one perhaps).

What code is that? If it's an emergency and the water heater is disconnected from the panel then what code is being violated here?


ArgMeMatey

join:2001-08-09
Milwaukee, WI
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reply to garys_2k

Re: Generator doesn't work with Power Vent Hot Water Heater

said by garys_2k:

Nobody is talking (here) about connecting between the house wiring and a generator, other than the ground.
...
As for the linemen, they treat all wires as hot and short the primaries together and then to ground before messing with them. They're well aware of the risks and realities of improperly connected generators.

1) I was referring to this subthread and similar posts ... »Re: Generator doesn't work with Direct Vent Hot Water Heater

2) I was thinking about places where a secondary cable feeds more than one home. If one customer connects their generator and fails to turn off the main, the secondary is backfed. I am guessing this would often just trip the generator breaker because of the loads that are still connected, but if it didn't, another customer doing their own hot-wire setup, not thinking like a professional line worker, could get a shock.
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Frink
Professor
Premium
join:2000-07-13
Scotch Plains, NJ
reply to tp0d

Re: Generator doesn't work with Direct Vent Hot Water Heater

Click for full size
said by tp0d:

said by Frink:

Everyone's advice is totally appreciated, and I understand the risks completely. That being said, bathing my 2 & 3 year old this morning in water that would not make them scream made all of us a lot happier...

So you got it to work? Bonding N to GND did it?

-j

Yup!

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
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reply to ArgMeMatey

Re: Generator doesn't work with Power Vent Hot Water Heater

Oh, I forgot about THAT suggestion, yeah, bad bad bad. So easy to mix up the switching, kind of like 1) drop the magazine, then 2) clear the chamber. Don't mix those up, either!

I've also thought that it'd be likely that a home generator would just drop its breaker if the main was thrown, may be more of a real safety hazard in rural areas where there may be only one house on a long stretch of line. In any case, it's not anything that should be possible to happen, even by mistake.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to garys_2k

said by garys_2k:

said by robbin:

Gas water heater / generator / extension cord / neutral ground bond. It connects to the electric system of the house. It is not isolated.

How's that? If the water heater is disconnected from the breaker, then connected to the generator via an extension cord, the generator's ground and neutral are bonded and then the generator's frame is connected (bonded, ideally) to the house ground, HOW are they "not isolated?"

Well, I can quote you multiple times in this thread where you stated that a proper bond to ground was not required. However my original point, which you would know if you had read my prior posts, is that the water heater is still connected to the house via the ground system on metal water pipes as well as the gas line. This creates hazards. Especially with multiple extension cords laying around.

said by garys_2k:

Nobody is talking (here) about connecting between the house wiring and a generator, other than the ground.

Why do you believe that the generator neutral is not connected to the entire house ground and neutral via the neutral / ground bond as I have described??

sk1939
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Mclean, VA
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reply to garys_2k

Re: Generator doesn't work with Direct Vent Hot Water Heater

said by garys_2k:

You did say "dead short." If you want to now talk about an overload, that's fine, but I can't see how any fault current would be available elsewhere on the system. The fault current would run back to the source, the generator.

True, if that was the only thing connected to the generator, and that the hot water heater wasn't connected to the house's ground/neutral system via the water pipes.

said by garys_2k:

What code is that? If it's an emergency and the water heater is disconnected from the panel then what code is being violated here?

An emergency is if you need hot water to give birth or treat critical injuries. It is not an emergency to take a warm shower when the power is out for 6 hours. As far as code, using flexible cable for a hardwired appliance. Minor when compared to the neutral/ground issue though when you account for the risk of energizing the neutral/ground.


TheTechGuru

join:2004-03-25
TEXAS
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Reviews:
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said by sk1939:

An emergency is if you need hot water to give birth or treat critical injuries. It is not an emergency to take a warm shower when the power is out for 6 hours.

6 hours? Try 6 to 16 days!!!

Anyway, our 8000 watt john deer ran our 4000 watt normal conventional 30 gallon water heater just fine after Ike.

Thing is, from my understanding, the OP's water heater is gas, but since it's electronically controlled with fan forced exhaust he could run it off a 200watt generator but it has to be wired right.

Modern things sure are a PITA aren't they. That's why I drive 20yr old cars.
--
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alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to robbin

Re: Generator doesn't work with Power Vent Hot Water Heater

said by robbin:

However my original point, which you would know if you had read my prior posts, is that the water heater is still connected to the house via the ground system on metal water pipes as well as the gas line. This creates hazards. Especially with multiple extension cords laying around.

Why do you believe that the generator neutral is not connected to the entire house ground and neutral via the neutral / ground bond as I have described??

1 - Multiple extension cords laying around, but plugged in the generator, is a hazard by itself.

2 - Yes the generator would be effectively bonded to the house's ground through the copper pipes of the water heater. But what's your point? All ground systems should be bonded, even if they are from separately derived systems.

2.1 - Maybe you're thinking that the house's N/G bond is considered as a SECOND N/G bond, but that's incorrect, because the generator's neutral isn't connected to the house's neutral through a second line.


pike
Premium,MVM
join:2001-02-01
Washington, DC
kudos:3
reply to alkizmo

Re: Generator doesn't work with Direct Vent Hot Water Heater

said by alkizmo:

THINK OF THE ETHIOPIANS!

First the trunk-slammer electrical advice...

Followed up with off-topic racist stereotypes.

Classy.


Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom

said by pike:

said by alkizmo:

THINK OF THE ETHIOPIANS!

First the trunk-slammer electrical advice...

Followed up with off-topic racist stereotypes.

Classy.

And what does this have to do with the topic?

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
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1 edit
reply to sk1939

said by sk1939:

said by garys_2k:

You did say "dead short." If you want to now talk about an overload, that's fine, but I can't see how any fault current would be available elsewhere on the system. The fault current would run back to the source, the generator.

True, if that was the only thing connected to the generator, and that the hot water heater wasn't connected to the house's ground/neutral system via the water pipes.

??

If there's a fault in the heater that sends current to ground, then yes, then (at least some, possibly all) the fault current may run through the piping system.

If the piping system was bonded to the electrical ground then that current would flow, via that bond, back to the generator. The voltage available on the pipes would be equal to the resistance drop from the heater to the generator, likely under five or so volts.

If the piping system was not bonded to ground, it could raise the pipe's voltage to lethal levels, EXACTLY what would happen if the generator was not being used and the heater was still running on utility power.

The generator's not making the situation worse, nor would it make it better. Either the generator or the utility could cause a fatal shock if the plumbing system wasn't properly bonded to ground.

The lesson here, I think, is fairly simple:
- Some devices require a neutral-ground bonded source
- A generator's ground should be connected, ideally bonded, to the house's ground system
- The plumbing system should be grounded whether or not a generator is in use.

Agree?

Oh, and I agree that having extension cords running around can be hazardous -- they should be secured out of the way of causing tripping or from being damaged.

Edit to fix some grammar issues...


TheTechGuru

join:2004-03-25
TEXAS
kudos:2
Reviews:
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1 edit
reply to Frink

Re: Generator doesn't work with Power Vent Hot Water Heater

Again, simply wireing the two hot legs, common, and ground directly to the main bus panel is the safest, easiest solution providing you know what you're doing and turn off the main breaker so that you do not backfeed.

Ok, many of you may have your main panel inside the house and just a meter outside.

Well in a emergency like this, I would cut off the seal on the damn thing and pull the meter out and store it somewhere safe where the glass isn't going to get broken. Then connect the generator to the lugs on the bottom of the meter area being careful not to touch any of the top lugs "just in-case" the power comes back on while you're doing the wiring.

Do note, if you're tryin to do this with a small 120volt only generator you're going to need to make a bridge to feed both rails with the 120V feed so both legs of the house have 120V (or only half the house lights will work). 240V appliances in the house will just see 0V on the two hot legs but will still see 120V hot to common. So your clothes dryer light, oven light and clock will probably work but they won't get hot if attempted to use.

It's a whole lot easier to just have one of these:

»www.tractorsupply.com/generac-re···-4208359

--
CompTIA Network+ Certified



DAJ

@myvzw.com
reply to garys_2k

Re: Generator doesn't work with Direct Vent Hot Water Heater

I have read the 5 pages of responses here and I just wanted to be clear. Assuming one only has a portable generator NOT connected to the house beyond extension cords (no transfer switch) is using the generator's grounding screw connected to a proper ground able to solve the neutral/grounding issue for the hot water? It sounds like the 6" extension cord modification does the trick but I was hoping for something a little more mainstream.


garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
·Callcentric
·callwithus

said by DAJ :

I have read the 5 pages of responses here and I just wanted to be clear. Assuming one only has a portable generator NOT connected to the house beyond extension cords (no transfer switch) is using the generator's grounding screw connected to a proper ground able to solve the neutral/grounding issue for the hot water? It sounds like the 6" extension cord modification does the trick but I was hoping for something a little more mainstream.

No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.

To make the fix more mainstream you'd want to make a permanent connection in the generator's electrical panel, screwing down one of the neutral wires to the generator's frame (which should already be connected to its outlets' ground wires).


TheTechGuru

join:2004-03-25
TEXAS
kudos:2
Reviews:
·HughesNet Satell..
·WesTex Connect

said by garys_2k:

No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.

Connecting BOTH the common AND ground from the generator to the common/ground rail in the main circuit panel of the house will fix the problem and while one is in there might as well connect the hot(s) from the generator to the appropriate rails in there. Just turn off the main so you don't back feed.
--
CompTIA Network+ Certified


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

1 edit
reply to DAJ

said by DAJ :

It sounds like the 6" extension cord modification does the trick but I was hoping for something a little more mainstream.

The proper way is to open up the receptacles panel on the generator and put a jumper wire behind the breakers between the neutral and ground using a 10AWG copper wire on the biggest lugs you can find that are linked to neutral and ground.

However, it can be tricky to open up that panel. Mine was sealed pretty tight, and I didn't have a lot of wire lenght to pull out the panel without disconnecting it completely from the generator (Which would have been very tricky as well).

Here's what I did for my mainstream setup:

My transfer switch handles the hot AND the neutral, so when I switch to the generator, the N/G bond in my electrical panel is no longer in the mix.

My generator's ground is still linked to the house ground through a #6 bare copper. That wire goes from the generator's ground lug and is tied by a split bolt to the house's ground conductor (Another #6 bare copper that is tied to my cold water copper pipe).

So with the N/G bond from the electrical panel broken because the transfer switch cuts the neutral off, I had to make a N/G bond at the generator. What I did is jump the neutral and ground from the inside of the L5-20P (plug) that connects to the generator to feed my transfer switch.

That way, when I connect my generator to the house transfer switch, the bond is created. When I disconnect the generator from the house, the bond is broken. No permanent modifications need to be done/undone on the generator itself.

Is it proper? Yup. The N/G bond is as close to the source (Generator) as it needs to be. The N/G bond cannot be removed without disconnecting the generator from the house. The ground bare copper wire still remains connected to the house ground, but that is of no impact, because there is no more bond between ground/neutral. It just helps avoiding static build up on the generator chassis if it is running but not connected to the house.

garys_2k
Premium
join:2004-05-07
Farmington, MI
Reviews:
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reply to TheTechGuru

said by TheTechGuru:

said by garys_2k:

No, connecting the generator's ground terminal to the house's ground system will NOT change the generator's neutral-ground bond type. Definitely DO connect the generator's ground to the house's ground, but using the cord will "fix" that bond issue.

Connecting BOTH the common AND ground from the generator to the common/ground rail in the main circuit panel of the house will fix the problem and while one is in there might as well connect the hot(s) from the generator to the appropriate rails in there. Just turn off the main so you don't back feed.

That's where we part ways. Connecting the generator's neutral and ground to the panel's common rail is fine, but tying the generator's hots to the panel's hot rails and turning off the main is NOT what I'd do.

Some panels have more than one "main" (six lever rule), no wires should connect directly to the rails (should go through a breaker) and a physical method of preventing both the main(s) and the generator's feed breaker from both connecting to the hot rails at the same time should be used, even for temporary or emergency use.

Since the more recent questions are regarding this one use (hot water heater that needs its power source to have N-G bond) then I'd leave the panel closed and do my wiring at the heater PLUS the ground line from the generator's ground terminal to the electrical system's ground.

ke4pym
Premium
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Charlotte, NC
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reply to sk1939

said by sk1939:

Again yes, but you can't really (even if you could it would be wrong because it's against code) power a water heater off of an extension cord (other than a tankless single sink one perhaps).

Wanna bet?

My tankless whole house would work great on an extension cord!

But I get your point.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

1 edit
reply to alkizmo

Re: Generator doesn't work with Power Vent Hot Water Heater

said by alkizmo:

2 - Yes the generator would be effectively bonded to the house's ground through the copper pipes of the water heater. But what's your point? All ground systems should be bonded, even if they are from separately derived systems.

The safety of a floating neutral generator is inherent in the design as since there is no ground, there is no shock or electrocution hazard from say standing in a wet puddle. The only way to be part of the current path is by touching both hot and neutral. Once the generator has a neutral ground bond added, this is no longer the case. My point is that the water heater is not isolated from the house as was posted. The entire house ground system is now energized. As a result, there are now many ways to receive an unhealthy or killing shock.

The fact that the Power Vent water heater only draws about 2 amps virtually guarantees that other devices will be powered concurrently with the water heater. As the generator has not been fully installed as code would require means that there is no shock protection for the house residents. Yes, every outlet in your kitchen has GFCI protection, but that extension cord coming in through the window does not (floating neutral generators do not have GFCI protection).

The generator as shipped by the manufacturer does not need to be grounded as it is isolated by design. There is nothing unsafe about using the generator without grounding it if it is used as it was designed to be used -- with extension cords only. Remember, the reason we need protection from ground faults is that our electrical distribution system is an earthed system, meaning that ground is part of the entire system. This is not the case with a portable, floating neutral generator. Generators which come with ground bonds also come with GFCI protection.


DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
kudos:2
reply to Frink

Re: Generator doesn't work with Direct Vent Hot Water Heater

said by Frink:

said by DKS:

And how many children do you have?

I already discussed that I have two, a 2 and a 3 year old, both in diapers

I have six children. I stand by what I said. Cold water will not hurt them one bit.
--
Need-based health care not greed-based health care.


GenNewbie

@rr.com
reply to garys_2k

Thanks for all of the replies. Here is what I have and what I plan to do. My house is 10 years old so has a relatively modern electric system. There is no PEX or plastic supply lines in the water supply system, it is 100% copper pipe. My main water supply line comes in near the main 200 amp electric panel and is grounded via a thick unsheathed cooper wire. I can see that ground wire running between the water supply and service panel, they are only about 6 feet away from each other. I can also see a clear cooper run of pipe that goes from that area, across the basement to supply cold water to my propane hot water heater. The hot water heater has the same thick braided copper wire jumping hot and cold pipe on the water heater. Based on this I ASSUME that the jumper is a proper ground as I can see the clear, uninterupted run of cooper pipe, the hook up to the main panel and the jumper on the water heater.

If I make-up the modified extension cord (thanks for the picture it confirmed what I needed to do!) and tie the generator ground into the exposed jumper/ground on the water heater (which I truly believe to be 100% grounded based on the above), it is as safe as it can get?



GenNewbie

@rr.com
reply to Frink

Thanks for the picture, worth at least 1,000 words! If I have a heavy duty plug head and some 12/2 romex already on hand, is there any reason I can't just make a similar cord up? I think that would allow me to make sure the hot prong and wire are isolated and maybe even remove the hot prong completely instead of having to cut it off? Sorry I'm cheap too.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to robbin

Re: Generator doesn't work with Power Vent Hot Water Heater

said by robbin:

The entire house ground system is now energized. As a result, there are now many ways to receive an unhealthy or killing shock.

it would normally trip the breaker on the generator (Or stall the generator) as the current would be flowing back to the neutral.

said by robbin:

The only way to be part of the current path is by touching both hot and neutral.

See I never knew that. I thought that no matter the source of current, you'd get shocked (Unless you were completely rubber proofed from touching anything that would conduct current to the ground).

I guess a precaution would be a GFCI protected extension cord.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

said by alkizmo:

said by robbin:

The entire house ground system is now energized. As a result, there are now many ways to receive an unhealthy or killing shock.

it would normally trip the breaker on the generator (Or stall the generator) as the current would be flowing back to the neutral.

Breakers provide overcurrent protection to prevent fires. They do not protect human life.

said by alkizmo:

said by robbin:

The only way to be part of the current path is by touching both hot and neutral.

See I never knew that. I thought that no matter the source of current, you'd get shocked (Unless you were completely rubber proofed from touching anything that would conduct current to the ground).

There was no ground and no need for it until the user followed your advice. Forget about ground, you need two conductors to complete a circuit. Ground is not one of them with a floating neutral generator.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

said by robbin:

Breakers provide overcurrent protection to prevent fires. They do not protect human life.

Right, but unless the short occurs while your touching something grounded, the breaker would trip quickly.

You're describing something that can happen with utility power in house circuits.

robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1

I am talking about human life. What you recommended provides no safety. It is dangerous.

No, it cannot happen to the same degree with utility power if the house is less than 30 years old. They have GFCI protection on at least some circuits. You have both a baby and inlaws from out of the country in your home. Would you want either of them exposed to the shock hazard I have described? Put another way, if your house had no GFCIs in either the kitchen or the bathroom, would you feel comfortable with your family's safety?


sk1939
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Mclean, VA
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1 recommendation

reply to alkizmo

said by alkizmo:

said by robbin:

Breakers provide overcurrent protection to prevent fires. They do not protect human life.

Right, but unless the short occurs while your touching something grounded, the breaker would trip quickly.

You're describing something that can happen with utility power in house circuits.

No, actually breakers don't trip unless you ground the circuit or overload the circuit. It takes very little current to stop your heart, which is why GFCI's trip so low. You get shocked when you complete the circuit by providing a path to ground. Ground potential is important here.

Generator and utility power isn't that different.


pike
Premium,MVM
join:2001-02-01
Washington, DC
kudos:3

1 recommendation

reply to alkizmo

said by alkizmo:

See I never knew that.

Precisely why you should refrain from dispensing electrical advice on a home improvement forum.